Linard Boris, Bézieau Stéphane, Benlalam Houssem, Labarrière Nathalie, Guilloux Yannick, Diez Elisabeth, Jotereau Francine
Institut de Biologie, Institut National de la Santé et de la Recherche Médicale, Unité 463, and Faculté des Sciences et Techniques de Nantes, Nantes, France.
J Immunol. 2002 May 1;168(9):4802-8. doi: 10.4049/jimmunol.168.9.4802.
Ags derived from commonly mutated oncogenic proteins seem ideally suited as targets for tumor immunotherapy. Nonetheless, only a few mutated epitopes efficiently presented by human tumors have thus far been identified. We describe here an approach to identify such epitopes. This approach involves: 1) identifying tumors expressing a ras mutation and isolating the tumor-infiltrating lymphocytes (TIL); 2) transfecting COS cells to induce expression of unknown mutated peptides in the context of a patient's HLA class I molecules; and 3) screening epitope recognition by using TIL from the tumors expressing a ras mutation. By using this approach, there appeared to be a N-ras mutation (a glutamine-to-arginine exchange at residue 61 (Q61R)), detected in a melanoma lesion, which was recognized specifically by the autologous TIL in the HLA-A0101 context. The ras peptide 55-64(Q61R) was the epitope of these TIL and was regularly presented by Q61R-mutated HLA-A0101(+) melanoma cell lines. This peptide and its wild-type homolog (55-64(wt)) bound to HLA-A*0101 with similar affinities. However, only the mutated peptide could induce specific CTL expansion from PBL. All the CTL clones specific to the mutated peptide, failed to recognize the wild-type sequence on both COS and melanoma cells. These data thus show that oncogenic protein mutations can create shared tumor-specific CTL epitopes, efficiently presented by tumor cells, and that screening for oncogene-transfected COS cell recognition by TIL (from tumors containing mutations) is a powerful approach for the identification of these epitopes.
源自常见突变致癌蛋白的抗原似乎是肿瘤免疫治疗的理想靶点。然而，迄今为止，仅鉴定出少数能被人类肿瘤有效呈递的突变表位。我们在此描述一种鉴定此类表位的方法。该方法包括：1）鉴定表达ras突变的肿瘤并分离肿瘤浸润淋巴细胞（TIL）；2）转染COS细胞以在患者的HLA I类分子背景下诱导未知突变肽的表达；3）使用来自表达ras突变的肿瘤的TIL筛选表位识别。通过使用这种方法，在一个黑色素瘤病变中检测到似乎存在一种N-ras突变（第61位残基处谷氨酰胺到精氨酸的交换（Q61R）），其在HLA-A0101背景下被自体TIL特异性识别。ras肽55-64（Q61R）是这些TIL的表位，并由Q61R突变的HLA-A0101（+）黑色素瘤细胞系定期呈递。该肽及其野生型同源物（55-64（wt））以相似的亲和力与HLA-A*0101结合。然而，只有突变肽能诱导外周血淋巴细胞（PBL）产生特异性CTL扩增。所有针对突变肽的CTL克隆均无法识别COS细胞和黑色素瘤细胞上的野生型序列。因此，这些数据表明致癌蛋白突变可产生由肿瘤细胞有效呈递的共享肿瘤特异性CTL表位，并且通过TIL（来自含有突变的肿瘤）筛选癌基因转染的COS细胞识别是鉴定这些表位的有力方法。
